Custom classloader that breaks parental delegation

Steps to break parental delegation ：

1、 Inherit ClassLoader

2、 rewrite loadClass、findClass

Code implementation ：

package ljxwtl;

import org.apache.commons.io.IOUtils;

import java.io.*;

/**
 * @author: wtl
 * @License: (C) Copyright 2022, wtl Corporation Limited.
 * @Contact: [email protected]
 * @Date: 2022/2/15 9:58 AM
 * @Version: 1.0
 * @Description:
 */
public class CustomClassLoader extends ClassLoader{

    @Override
    public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
        synchronized (getClassLoadingLock(name)) {
            // First, check if the class has already been loaded
            Class<?> c = findLoadedClass(name);
            if (c == null) {

                if (!name.startsWith("ljxwtl")){
                    c = super.loadClass(name,resolve);
                }
                else{
                    // If still not found, then invoke findClass in order
                    // to find the class.
                    c = findClass(name);
                }
            }
            if (resolve) {
                resolveClass(c);
            }
            return c;
        }
    }

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        String classPath = name.replaceAll("\\.","/");

        InputStream inputStream = CustomClassLoader.class.getResourceAsStream("/" + classPath + ".class");
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

        try {
            IOUtils.copy(inputStream,byteArrayOutputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }

        byte[] classBytes = byteArrayOutputStream.toByteArray();

        return defineClass(name,classBytes,0,classBytes.length);
    }
}